Hartford's office market vacancy rate is at a 10-year low and gaining momentum, and the departure of Aetna's headquarters is not expected to disrupt progress significantly, according to a new report.

Toronto-based Avison Young's Mid-Year 2017 North America and Europe Office Market Report, released Thursday, covers 64 metropolitan North American and European markets.

According to the report, Hartford's overall vacancy rate is at 12.5 percent, but that's expected to rise in 2018, when Aetna moves its headquarters to New York City. "Aetna's footprint is expected to be backfilled quickly," however, the report said.

"With city rents comparable to the suburbs, companies outside of the city may view this situation as an opportunity as Hartford's downtown area continues to improve," the report states.

Hartford leaders are hoping for a resurgence in activity downtown, with the influx of UConn students in a couple weeks to the new UConn downtown campus. The city also has added activity with the debut of the Hartford Yard Goats at Dunkin' Donuts Park.

Key office leases in the first half of 2017 included Connecticut Children's Medical Center, United Bank and Conning & Co., the report states.

Downtown Hartford rents averaged $23.38 per square foot, but the small price difference with the suburbs, which averaged $22.66 per square foot, was larger than historical norms, due to a tightening of space in the city "with no significant office construction efforts insight," the report found.